Stationary type solar energy collector apparatus

Abstract

A hybrid collector for collecting solar energy comprised of a plurality of parabolic reflectors cooperating with tube/fin type fluid carrying collector elements, selective ones of which are arranged at the focal points of the parabolas. Additional tube/fin elements are positioned at a spaced distance above the boundary line between adjacent parabolic reflectors. The exterior surfaces of the tube/fin collector elements are treated preferably with a selective coating to provide high absorptivity and low emissivity. The surface areas of the tube/fin elements are also reduced to further contribute to a reduction in emissivity to optimize total absorptance. Location of the tube/fin elements which are off the parabolic reflector focal points cooperate with those located at the focal points to absorb diffuse energy while the tube/fin elements at the focal points absorb beam energy providing for both absorption of beam energy on clear sunny days and absorption of diffuse energy on cloudy or overcast days. The positioning of the tube/fin collectors well above the reflectors takes advantage of convection currents to increase energy transfer by reduction of energy loss. The structure provides the above functions through a fully stationary mounting. The parabolic reflector structures comprise flexible reflector sheets mounted within supporting troughs which are adapted to slideably receive the reflective sheets and urge the sheets into perfect parabolic configurations due to the geometry and interrelationship of the troughs and the reflective sheets, yielding a perfect parabolic reflector produced in an inexpensive manner.

What is claimed is: 
     
       1. A solar energy collector for collecting and absorbing solar energy in the form of both beam type and diffuse type radiation comprising: a housing having one transparent side;   a parabolic reflector within said housing facing said transparent side for reflecting beam type radiation passing through said transparent side;   an elongated fluid carrying element having its longitudinal axis substantially aligned with the focal line of said parabolic reflector, said elongated fluid carrying element being hollow and having a first substantially planar surface facing said parabolic reflector to receive and absorb radiation reflected from said reflector, said elongated fluid carrying element comprising a first fluid carrying element, and second and third fluid carrying elements positioned parallel to and on opposite sides of said first fluid carrying element, said second and third fluid carrying elements each having a first flat surface remote from said reflector and positioned over the longitudinal side edge thereof for collecting and absorbing diffuse type solar radiation passing through said transparent side and a second flat surface facing said parabolic reflector for absorbing heat resulting from convection currents developed between said fluid elements and said parabolic reflector.   
     
     
       2. The apparatus of claim 1 wherein said elongated fluid carrying elements each has a second substantially planar surface parallel to said first planar surface and arranged to receive and absorb diffuse radiation passing through said transparent side of said housing. 
     
     
       3. The apparatus of claim 2 wherein said first and second planar surfaces are covered with a coating for absorbing solar radiation at a high level of efficiency. 
     
     
       4. The apparatus of claim 2 wherein said elongated fluid carrying elements have a rectangular cross-sectional configuration. 
     
     
       5. The apparatus of claim 2 wherein said elongated fluid carrying elements further comprise a hollow tube having at least one radially aligned fin extending outwardly from and integral with said tube. 
     
     
       6. The apparatus of claim 1 further comprising means for introducing fluid into one end of said elongated fluid carrying elements and means for delivering fluid exiting from the opposite end of said elements to an energy utilization means. 
     
     
       7. The apparatus of claim 1 wherein said housing transparent side comprises a pair of transparent sheets arranged in spaced parallel fashion and sealing means for sealing said sheets across the transparent side of the housing. 
     
     
       8. The apparatus of claim 1 further including supply and return manifolds for introducing fluid into said fluid carrying elements to be heated by radiation absorbed by said fluid carrying elements and for receiving and conducting said heated fluid to a heat energy utilization means. 
     
     
       9. The apparatus of claim 7 further comprising means for adjustably aligning the housing so that its transparent side is diagonally aligned relative to an imaginary horizontal plane at an angle chosen to optimize the radiant solar energy captured by said elements. 
     
     
       10. A stationary mounted solar energy collector means adapted to absorb solar energy without tracking the sun, said solar energy collector apparatus comprising: a box-like housing having one open side;   transparent means in said open side for sealing said open side while permitting the passage of solar radiation therethrough;   a plurality of parabolic concave reflectors mounted side-by-side within said housing, each of said concave reflectors facing said open side of said housing for reflecting beam type radiant energy passing through said open side and concentrating the reflected rays towards the focal line of said reflector;   a first plurality of elongated fluid carrying elements within said housing, each of said elongated fluid carrying elements having its longitudinal axis substantially aligned with one of said focal lines of said concave reflectors and having a substantially flat surface coated with a radiation absorptive coating for absorbing radiation directed thereto by said concave reflector;   a second plurality of fluid carrying elements each positioned in spaced parallel fashion and interspersed with said first plurality of fluid carrying elements, said second plurality of fluid carrying elements each having first substantially planar surfaces facing said concave reflectors, and said second plurality of fluid carrying elements lying a sufficient distance above said concave reflectors to enable said first substantially planar surfaces to absorb heat energy developed by convection currents created in said housing and above said reflectors; and   means for introducing fluid into said first, second and third fluid carrying elements and means for withdrawing the fluid introduced into said first, second and third fluid carrying elements for delivery to a heat energy utilization means, said second plurality of fluid carrying elements arranged to overlie the longitudinal side edges of at least one reflector.   
     
     
       11. The apparatus of claim 10 further comprising U-shaped coupling means joining the ends of adjacent pairs of elements while the remaining ends are respectively coupled to said introducing means and said withdrawing means. 
     
     
       12. The apparatus of claim 11 wherein each of said elements comprises a hollow tube having at least one radially aligned fin extending outwardly from and integral with said tube. 
     
     
       13. The apparatus of claim 12 wherein the exterior surface of said elements are treated with a selective coating having a high absorptivity and a low emissivity of solar radiation.